GPS/GNSS Symposium 2010

QZSS LEXによるリアルタイムPPP実験とその拡張Real Time PPP Experiment via QZSS LEX and its ExtensionReal‐Time PPP Experiment via QZSS LEX and its Extension

Tokyo University of Marine Science and Technology

Tomoji TAKASUTomoji TAKASU

OutlineOutline

• What is PPP?• Real‐Time PPP Experiment via QZSS LEXReal Time PPP Experiment via QZSS LEX• Real‐Time PPP Client Implementation• Preliminary Performance Evaluation• Future Extension of QZSS LEX PPPFuture Extension of QZSS LEX PPP• Summary

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What is PPP?

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PPP: Precise Point PositioningPPP: Precise Point Positioning

• Carrier‐Based Single Positioning with GNSS– Dm to mm‐level accuracy– No need base‐station and baseline– Global coverage world‐wide– Need precise orbit and clock– Conventionally post‐processing– Start to utilize it in real‐time

UserReceiver

Base‐Station

Baseline

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ReceiverStation

Comparison of RTK and RT PPPComparison of RTK and RT‐PPPRTK/Network RTK Real Time PPPRTK/Network‐RTK Real‐Time PPP

Coverage <100 km from Base Global

Accuracy 2 cm HRMS <10 cm HRMS

Convergence < 30 s 30 min

Ionosphere Eliminated by DD Dual‐Frequency

Ambiguity Fixed Float

Orbit/Clock Broadcast Precise

Communication Point To Point Satellite, Internet

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Communication Point To Point Satellite, Internet

Example of PPP AP (1/2)2010/1/27 M8 8 Chilean

Example of PPP AP (1/2)2010/1/27 M8.8 Chilean

Earthquake

IGS CONZ, Orbit/Clock: CODE/CODE‐5 s2010/2/27 6:28 6:45 1 Hz RTKPOST 2 4 0

66http://earthquake.usgs.gov/earthquakes

2010/2/27 6:28‐6:45 1 Hz, RTKPOST 2.4.0,Mode: Kinematic PPP + Combined, GPS

Example of PPP AP (2/2)Example of PPP AP (2/2)

100 km100 km

GPS TsunamiMonitoring System

( l k ff h )1,000 km

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(Currently ~20 km off‐shore)http://www.tsunamigps.com

Commercial RT PPP ServiceCommercial RT‐PPP ServiceProvider Service Coverage Broad‐ Ref. Orbit/ Engine AccuracyProvider Service Coverage cast Stations Clock Engine Accuracy

N C St Fi World‐ 3 GEO 60 1 min/ JPL <10 cm H15 VNavCom StarFire wide L‐band 60 /

1‐2 s RTG <15 cm V(1 sigma)

World

Fuguro

OmniSTARXP/HP+

World‐wide(Land)

6 GEOL‐band 100 1 min/

10 s Fuguro dm‐class

Fuguro

SeaSTARXP/G2

World‐wide(Sea)

6 GEOL‐band 100 1 min/

10 s

Fuguro/ESOC(G2)

dm‐class

VERIPOS VERIPOSUltra/Apex

World‐wide

7 GEOL‐band 80 30 s/

30 sJPL/ESOC

10 cm H20 cm V( %)

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Ultra/Apex wide L band 30 s ESOC (95%)

IGS RT Orbit/ClockIGS RT Orbit/Clock

• Developed by IGS RTPP– Corrections to broadcast ephemeris– RTCM v.3 MT1057‐1068 (SSR)– NTRIP stream via Internet– Interval: 10 s, Latency: 5 ‐ 10 s– Free of charge

• Provided by several ACs– Orbit: fixed to IGU or estimated– Clock: estimated with IGS real‐timetracking network http://igs.bkg.bund.de

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Real‐Time PPPReal‐Time PPPExperiment via QZSS LEX

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QZSS LEX SignalQZSS LEX SignalSpecificationSpecification

Frequency 1278.75MHz (= Galileo E6 CS)

Bandwidth 42.0MHz

Signal Power ‐155 7dBW (Min)Signal Power 155.7dBW (Min)

Modulation BPSK (5) , Short‐Kasami‐Sequence

SpreadingCode

Short Period: 4ms, Length: 10,230 chips

Long Period: 410ms Length: 1 048 575 chipsLong Period: 410ms, Length: 1,048,575 chips

Navigation Data 2000 bits/frame, 1 frame/s

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QZSS LEX MessageQZSS LEX Message

2000 bits / 1s

RS Code

Data Part (1695 bits)

Header(49 bits)

RS Code (256 bits)

Preamble (32 bits)

PRN (8 bits)Message Type ID (8 bits)

12Alert Flag (1 bit)

QZSS LEX Message Type IDQZSS LEX Message Type IDMT ContentsMT Contents

0‐9 Reserved

10 19 JAXA E i10‐19 JAXA Experiment

10 Signal Health (35 Satellites)E h i d SV Cl k (3 S t llit )Ephemeris and SV Clock (3 Satellites)

11Signal Health (35 Satellites)Ephemeris and SV Clock (2 Satellites)11 Ephemeris and SV Clock (2 Satellites)Ionosphere Correction

12‐19 Reserved12 19 Reserved20 GSI Experiment

21 255 Other Experiment

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21‐255 Other Experiment

JAXA Experiment (1/2)JAXA Experiment (1/2)

• Signal Health– 32 GPS + 3 QZSS, L1, L2, L5, L1C, LEX

• Ephemeris and SV Clock– 32 GPS + 3 QZSS satellites– 32 GPS + 3 QZSS satellites– 3nd order coefficients of ECEF position and URA

/– Clock bias/drift and DCB• Ionosphere Correction

– 2nd/1st order coefficients of vertical delay– Regional coverage near JapanRegional coverage near Japan

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JAXA Experiment (2/2)JAXA Experiment (2/2)

M I l (N i l)

Message Broadcast Update EffectiveP i d

Message Interval (Nominal)

g p Period

Signal Health 1 s 1 s ‐

Ephemeris 12 s 3 min 6 min

SV Clock 12 s 3 min 6 min

Ionosphere 12 s 30 min ‐

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Real‐Time PPP ClientReal‐Time PPP Client Implementation

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RTKLIBRTKLIB

• Open Source Program Package for GNSS Positioning– Whole source codes are freelyavailable

– License: GPLv3– >10,000 downloads (Total)

• Portable Library + Several APs– ANSI C + socket/pthread …/p– Portable command‐line APs– GUI APs for Windows

17http://www.rtklib.com

RTKLIB APsRTKLIB APs

STRSVRRTKCONV

NTRIPBROWS

RTKPLOTRTKNAVI

RTKPOST

RTKNAVI

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RTKLIB FeaturesRTKLIB Features

• Standard and precise positioning algorithms with:– GPS, GLONASS, SBAS (and Galileo, QZSS)

• Various positioning modes:– Single, SBAS, DGPS, RTK, Static, Moving‐base and PPPg g

• Supports many formats/protocols and receivers:– RINEX 2 2 RINEX 3 0 RTCM v 2 RTCM v 3 NTRIP 1 0RINEX 2.2, RINEX 3.0, RTCM v.2, RTCM v.3, NTRIP 1.0,NMEA0183, SP3, RINEX CLK, ANTEX, NGS PCV, …

– NovAtel, Hemisphere, u‐blox, SkyTraq, …, p , , y q,

• External communication via:– Serial TCP/IP NTRIP and file streams– Serial, TCP/IP, NTRIP and file streams

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RTKLIB 2 4 0RTKLIB 2.4.0

• Released on August 8, 2010• New Features:

– PPP‐Kinematic or PPP‐Static mode for both of real‐time and post‐processing

– Long baseline RTK up to 1,000 km– Supports RTCM v.3 MT1057‐1068 (SSR) for real‐time orbit and clock corrections

– Supports RINEX 3.0 for multi‐GNSS processing– Ready to support new GNSS (QZSS, Galileo, ...)– Real‐time and remote visualization by RTKPLOT

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PPP Features in RTKLIB 2 4 0PPP Features in RTKLIB 2.4.0

• Kalman‐Filter Based Parameter Estimator– PPP‐Kinematic or PPP‐Static mode

• Atmosphere Corrections:– Only L3‐LC with dual‐frequency for Ionospherey q y p– ZTD and gradient estimation with NMF

• Sold Earth Tide Model by IERS 2003 (subset)Sold Earth Tide Model by IERS 2003 (subset)• Satellite and Receiver Antenna PCV models

ANTEX (IGS05 ATX) or NGS– ANTEX (IGS05.ATX) or NGS

• Antenna Wind‐up Correction for Phase

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Static 24H PPP with IGS FinalStatic 24H PPP with IGS FinalGeonet

Repeatability after GEONET2110: 2009/1/1 12/31Geonet

StationLinear Fitting (mm)E‐W N‐S U‐D

0601 6 5 3 4 10 7

GEONET2110: 2009/1/1‐12/31

0601 6.5 3.4 10.70837 4.4 2.9 10.80369 3.3 2.4 8.1

E‐W

0579 3.1 2.2 8.60586 4.4 3.1 9.4

N‐S

0241 3.3 2.3 8.40324 3.6 2.4 8.80174 3 7 2 7 8 9

U‐D0174 3.7 2.7 8.93023 3.3 2.7 7.80905 3.7 2.8 8.1

5cm

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0905 3.7 2.8 8.1STD E/N/U: 3.0 2.3 7.4 mm

RT PPP with IGS RT Orbit/ClockRT‐PPP with IGS RT Orbit/ClockNovAtel, 2010/10/1 ‐10/14 1Hz with GSOC/DLR: CLK20E‐WE W

N‐S

U‐D

50cm

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RMS E/N/U: 4.9, 5.6, 10.1 cm

QZSS Extension for RTKLIBQZSS Extension for RTKLIB

• Support for QZSS satellites– Single, DGPS, RTK and PPP with QZSS– RINEX 2.2, RINEX 3.0, SP3, ANTEX and RTCM for QZSS

• Support for LEX MT 10 and 11pp– LEX message handling– Ephemeris and SV clock modelp– Ionosphere correction model– Single‐Frequency PPPg q y

• Support for LEX receiver proprietary message• Utility for post processing• Utility for post‐processing

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Future Plan of RTKLIBFuture Plan of RTKLIB

• v. 2.4.1: End of 2010– Fix problems and bugs

• v. 2.5.0: Spring or Summer 2011– SDR front end for GPS/GLONASS/QZSS (L1)( )– Support of Galileo/QZSS– Single‐Frequency PPPg q y– Improvement of PPP– Add supported formatspp– ...

25SDR prototype for RTKLIB 2.5.0

PreliminaryPreliminaryPerformance Evaluation

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Preliminary EvaluationPreliminary Evaluation

• LEX Data for JAXA Experiment– 2010/08/03 0:00:00‐23:59:59 24H– Generated in ground system Integration test– LEX MT 10, 11 only corrections for GPS– 13 Monitor Stations

• Post‐processing PPP Testp g– RTKPOST 2.4.0 + LEX extension– 4 GEONET stations 30 s x 24 H

• Positioning Mode– Kinematic PPP with L1/L2 and L1 only

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– Kinematic PPP with L1/L2 and L1 only

LEX GPS Orbit AccuracyLEX GPS Orbit Accuracy3

RMS Error 3D/R/A/C:112.9 , 18.3, 77.8, 77.0 cm

3

2.5

2

1.5

1

0.50.5

0

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Kinematic PPP with LEX CorrectionKinematic PPP with LEX CorrectionGEONET 0001 Wakkanai, 2010/8/3 0:00:00‐23:59:30

E‐W

N‐S

U‐D

1 m

29RMS E/N/U: 15.2, 14.2, 21.6 cm

LEX Experiment PlanLEX Experiment Plan

• January ‐March 2011• Evaluation of LEX PPP Performance

– Dual‐freq/Single‐freq PPP– Convergence Time of PPPg– Stationary and moving receiver

• Evaluation of LEX Orbit and ClockEvaluation of LEX Orbit and Clock– GPS orbit and clock– QZSS orbit and clockQZSS orbit and clock

• Evaluation of LEX Ionospheric Correction

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Future Extension ofFuture Extension ofQZSS LEX PPP

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Future LEX PPPFuture LEX PPP

• Real‐time PPP with multi‐GNSS– Real‐time orbit and clock for all GNSS available– Uniform time and coordinate among different GNSS

• PPP‐AR (ambiguity resolution)g y– Satellite‐side carrier‐phase bias correction– Need more precise orbit and clock (< 3 cm)p ( )

• Regional precise atmospheric corrections– STEC instead of VTEC for ionosphereSTEC instead of VTEC for ionosphere– ZTD/MF or 3D NWM for troposphere

• Bandwidth Limitation vs Target User/AP• Bandwidth Limitation vs. Target User/AP32

Summary

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SummarySummary

• What is PPP?– Applications– Real‐Time PPP

• RT PPP Experiment via QZSS LEXp• RT PPP Client Implementation with RTKLIB• Preliminary Evaluation Result• Preliminary Evaluation Result• Future Enhancement of LEX PPP

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